Braun tube and method of producing braun tubes



NOV. 30, 1937. 5 LQEWE I 2,100,697

BRAUN TUBE AND, METHOD OF PRODUCING BRAUN TUBES Filed Aug. 24, 1953 Jm enfo/z- 30 a tube Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE BRAUN TUBE AND METHOD OF PRODUCING BRAUN TUBES Siegmund Loewe, Berlin, Germany 1 Claim.

outgassed by means of methods of such nature.

in which a residual magnetization of the electrodes may safely be avoided.

According, therefore, to the invention, there are employed for outgassing the electrodes of Braun tubes methods of such nature in which a residual magnetization of the electrodes may safely be avoided.

In the following reference will be made to certain processes which enable the object of the invention to be accomplished in particularly simple fashion.

If outgassing by eddy current is made use of, it may be desirable to employ undamped high frequency, such as supplied for example by generator. When employing impulse spark generators the formation of residual magnetism may safely be avoided if the generator is connected up in such fashion that each two consecutive spark discharges act in opposite manner 35 on the outgassing coil. When employing a normal impulse spark generator it is desirable in accordance with the invention to allow the eddy current field to increase slowly and again fade as equally as slowly, employing very rapid se- 40 quence of the sparks (for example of the order of 10,000 per second) and operating with relatively small amplitudes. The transmitter itself should be preferably screened off in such fashion that its field is unable to affect the field of the out- 45 gassing coil. Naturally in all cases the formation of a D. C. component in the outgassing coil should be carefully avoided. If required, there may be provided for this purpose, say, a choke parallel to the outgassing coil.

The invention is diagrammatically illustrated in the single figure of the drawing which shows by way of example a Braun tube containing electrodes to be degasified and a device by means of which the degasification according to the invention may be performed. 10

In the drawing, l is the Braun tube containing electrodes such as 2, 3, 4, 5 to be degasified. 6 is a high frequency coil into the area of action of which the electrodes to be degasified are introduced. This coil is arranged in the consuming l5 circuit of a high frequency generator, e. g. as shown, an impulse spark generator which may be of any suitable type. The drawing shows a conventional arrangement in which a coil 1 connected in series with the coil 6 is adjustably coupled with 20 a coil 8 incorporated in the main oscillatory circuit of an impulse spark generator, which circuit is completed by a condenser 9 and the spark gap l0. Every two consecutive spark discharges have opposite polarities and accordingly act on the coil 6 in opposite directions. The required energy is fed in over a transformer of which the drawing shows only the secondary, II. The coupling between 1 and 8 may be varied as desired, and it may thereby be accomplished that the high fre- 39 quency currents through 6 slowly increase in their maximum amplitudes until the electrodes to be degasified are heated to the outgassing temperature and then increase slowly.

I claim:

In the process of degasifying electrodes consisting of magnetic material for Braun tubes the steps of arranging the electrode within the area of action of a high frequency coil, causing an eddy current field slowly to increase until the 40 electrode is heated to the outgassing temperature and causing said eddy current field hereupon slowly to decrease.

SIEGMUND LOEWE. 

